SIST-TP CEN/CLC/TR 17603-10-12:2021

Space engineering - Calculation of radiation and its effects and margin policy handbook

This handbook is a part of the System Engineering branch and covers the methods for the calculation of radiation received and its effects, and a policy for design margins. Both natural and man-made sources of radiation (e.g.
radioisotope thermoelectric generators, or RTGs) are considered in the handbook.
This handbook can be applied to the evaluation of radiation effects on all space systems.
This handbook can be applied to all product types w hich exist or operate in space, as w ell as to crew s of on manned space missions.
This handbook complements to EN 16603-10-12 "Methods for the calculation of radiation received and its effects and a policy for the design margin".

Raumfahrttechnik - Handbuch zur Berechnung von Strahlung, Strahlungseffekten und Marginregeln

Ingénierie spatiale - Manuel de calcul du transport des radiations et de leurs effets, et politique des marges

Vesoljska tehnika - Priročnik za izračun sevanja in njegovih učinkov ter za politiko pri načrtovanju mejnih vrednosti

General Information

• Status: Published
• Public Enquiry End Date: 17-Feb-2021
• Publication Date: 10-Oct-2021
• ICS: 49.140 - Space systems and operations
• Technical Committee: I13 - Imaginarni 13
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 06-Oct-2021
• Due Date: 11-Dec-2021
• Completion Date: 11-Oct-2021
• Mandate: M/496 - Mandate addressed to CEN, CENELEC and ETSI to develop standardisation regarding space industry (Phase 3 of the process)
• Ref Project: CEN/CLC/TR 17603-10-12:2021 - Space engineering - Calculation of radiation and its effects and margin policy handbook

Overview

SIST-TP CEN/CLC/TR 17603-10-12:2021 is a technical handbook in the space engineering domain that establishes methods for calculating radiation exposure, assessing radiation effects, and applying a policy for design margins. It covers both natural and man‑made radiation sources (for example radioisotope thermoelectric generators - RTGs) and is applicable to all space systems, product types operating in space, and crews on manned missions. This handbook complements EN 16603-10-12 ("Methods for the calculation of radiation received and its effects and a policy for the design margin").

Key topics and technical scope

The handbook provides a structured compendium of radiation topics essential to spacecraft design and operations, including:

• Radiation effects compendium - overview of effects on electronics, materials, payloads, biological tissue, and spacecraft charging.
• Margin policy - guidance on applying design margins to account for environment and effects uncertainties, test limitations, procurement variability and project decisions.
• Radiation shielding - principles of radiation transport (electrons, protons, heavy particles, bremsstrahlung), material selection, layout and add‑on shielding, and decision criteria for deterministic vs Monte Carlo or sector analyses.
• Total ionising dose (TID) - definitions, technologies susceptible to TID and calculation considerations.
• Displacement damage (NIEL) - modelling, equivalent fluence calculations, technologies affected and testing approaches.
• Single event effects (SEE) - modelling (LET, cross section, sensitive volume), test methods (heavy ion, proton/neutron), hardness assurance and mitigation.
• Radiation-induced sensor backgrounds - impacts on imaging, particle and photon detectors, and instrument noise.
• Biological effects and radiation protection - quantities, operational limits and effects relevant to crewed missions.
• Uncertainties and testing - beam/source characterization, representativeness, packaging, and other test‑related uncertainties.

Practical applications and users

This technical report is intended for practitioners who need to assess, mitigate or certify radiation effects in space systems:

• Space systems and spacecraft designers - to size shielding, select materials and design layouts that meet margin policies.
• Systems engineers and mission planners - to include radiation assessments in requirement flows, risk analyses and margin allocation.
• Payload and instrument engineers - to evaluate sensor backgrounds, TID, displacement damage and SEE susceptibility.
• Radiation test laboratories and verification teams - to align test methods and interpret uncertainties.
• Safety and crew health officers - for radiation protection guidance relevant to crewed missions and operational limits.
• Procurement and project managers - to define supplier requirements and account for device reproducibility and derating.

Related standards

• EN 16603-10-12 - Methods for the calculation of radiation received and its effects and a policy for the design margin (complementary document).
• CEN/CLC technical frameworks and national standards in space systems and operations.

This handbook is a practical reference for implementing robust radiation assessment, shielding design and margin strategies across both robotic and crewed space projects. Keywords: space engineering, radiation calculation, TID, NIEL, single event effects, shielding, design margins, RTG, space systems.

Standards Content (Sample)

SLOVENSKI STANDARD
01-november-2021
Vesoljska tehnika - Priročnik za izračun sevanja in njegovih učinkov ter za politiko
pri načrtovanju mejnih vrednosti
Space engineering - Calculation of radiation and its effects and margin policy handbook
Raumfahrttechnik - Handbuch zur Berechnung von Strahlung, Strahlungseffekten und
Marginregeln
Ingénierie spatiale - Manuel de calcul du transport des radiations et de leurs effets, et
politique des marges
Ta slovenski standard je istoveten z: CEN/CLC/TR 17603-10-12:2021
ICS:
49.140 Vesoljski sistemi in operacije Space systems and
operations
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

TECHNICAL REPORT
CEN/CLC/TR 17603-10-
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
September 2021
ICS 49.140
English version
Space engineering - Calculation of radiation and its effects
and margin policy handbook
Ingénierie spatiale - Manuel de calcul du transport des Raumfahrttechnik - Handbuch zur Berechnung von
radiations et de leurs effets, et politique des marges Strahlung, Strahlungseffekten und Marginregeln

This Technical Report was approved by CEN on 19 March 2021. It has been drawn up by the Technical Committee CEN/CLC/JTC
5.
CEN and CENELEC members are the national standards bodies and national electrotechnical committees of Austria, Belgium,
Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia,
Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

CEN-CENELEC Management Centre:
Rue de la Science 23, B-1040 Brussels
© 2021 CEN/CENELEC All rights of exploitation in any form and by any means Ref. No. CEN/CLC/TR 17603-10-12:2021 E
reserved worldwide for CEN national Members and for
CENELEC Members.
Table of contents
European Foreword . 9
1 Scope . 10
2 Terms, definitions and abbreviated terms . 11
2.1 Terms from other documents . 11
2.2 Terms specific to the present handbook . 11
2.3 Abbreviated terms. 11
3 Compendium of radiation effects . 12
3.1 Purpose . 12
3.2 Effects on electronic and electrical systems . 14
3.2.1 Total ionising dose . 14
3.2.2 Displacement damage . 14
3.2.3 Single event effects . 15
3.3 Effects on materials . 16
3.4 Payload-specific radiation effects . 16
3.5 Biological effects . 17
3.6 Spacecraft charging . 17
3.7 References . 17
4 Margin . 19
4.1 Introduction . 19
4.1.1 Application of margins . 19
4.2 Environment uncertainty . 20
4.3 Effects parameters’ uncertainty. 21
4.3.1 Overview . 21
4.3.2 Shielding . 21
4.3.3 Ionising dose calculation . 22
4.3.4 Non-ionising dose (NIEL, displacement damage) . 22
4.3.5 Single event effects . 22
4.3.6 Effects on sensors. 23
4.4 Testing-related uncertainties . 23

4.4.1 Overview . 23
4.4.2 Beam characteristics . 23
4.4.3 Radioactive sources . 23
4.4.4 Packaging . 24
4.4.5 Penetration . 24
4.4.6 Representativeness . 24
4.5 Procurement processes and device reproducibility . 24
4.6 Project management decisions . 25
4.7 Relationship with derating . 25
4.8 Typical design margins . 25
4.9 References . 25
5 Radiation shielding . 26
5.1 Introduction . 26
5.2 Radiation transport processes . 26
5.2.1 Overview . 26
5.2.2 Electrons . 26
5.2.3 Protons and other heavy particles . 28
5.2.4 Electromagnetic radiation – bremsstrahlung. 32
5.3 Ionising dose enhancement . 33
5.4 Material selection . 33
5.5 Equipment design practice . 33
5.5.1 Overview . 33
5.5.2 The importance of layout . 34
5.5.3 Add-on shielding . 34
5.6 Shielding calculation methods and tools – Decision on using deterministic
radiation calculations, detailed Monte Carlo simulations, or sector shielding
analysis . 36
5.7 Example detailed radiation transport and shielding codes . 45
5.8 Uncertainties . 45
5.9 References . 46
6 Total ionising dose . 48
6.1 Introduction . 48
6.2 Definition . 48
6.3 Technologies sensitive to total ionising dose . 48
6.4 Total ionising dose calculation . 50
6.5 Uncertainties . 50
7 Displacement damage . 51
7.1 Introduction . 51
7.2 Definition . 51
7.3 Physical processes and modelling . 51
7.4 Technologies susceptible to displacement damage . 55
7.4.1 Overview . 55
7.4.2 Bipolar . 56
7.4.3 Charge-coupled devices (CCD). 57
7.4.4 Active pixel sensors (APS) . 57
7.4.5 Photodiodes . 58
7.4.6 Laser diodes . 58
7.4.7 Light emitting diode (LED) . 58
7.4.8 Optocouplers . 58
7.4.9 Solar cells . 59
7.4.10 Germanium detectors . 59
7.4.11 Glasses and optical components . 60
7.5 Radiation damage assessment . 60
7.5.1 Equivalent fluence calculation . 60
7.5.2 Calculation approach . 60
7.5.3 3-D Monte Carlo analysis . 60
7.5.4 Displacement damage testing . 60
7.6 NIEL rates for different particles and materials . 61
7.7 Uncertainties . 68
7.8 References . 68
8 Single event effects . 70
8.1 Introduction . 70

8.2 Modelling . 71
8.2.1 Overview . 71
8.2.2 Notion of LET (for heavy ions) . 71
8.2.3 Concept of cross section . 71
8.2.4 Concept of sensitive volume, critical charge and effective LET . 72
8.3 Technologies susceptible to single event effects . 73
8.4 Test methods . 73
8.4.1 Overview . 73
8.4.2 Heavy ion beam testing . 73

8.4.3 Proton and neutron beam testing . 74
8.4.4 Experimental measurement of SEE sensitivity . 74
8.4.5 Influence of testing conditions . 75
8.5 Hardness assurance . 77
8.5.1 Rate prediction . 77
8.5.2 Prediction of SEE rates for ions. 77
8.5.3 Improvements . 79
8.5.4 Method synthesis . 80
8.5.5 Prediction of SEE rates of protons and neutrons . 80
8.5.6 Method synthesis . 82
8.5.7 Calculation toolkit . 82
8.5.8 Applicable derating and mitigating techniques . 82
8.5.9 Analysis at system level . 82
8.6 Destructive SEE . 83
8.6.1 Single event latch-up (SEL) and single event snapback (SESB) . 83
8.6.2 Single event gate rupture (SEGR) and single event dielectric rupture
(SEDR) . 85
8.6.3 Single event burnout (SEB) . 86
8.7 Non-destructive SEE . 87
8.7.1 Single event upset (SEU) . 87
8.7.2 Multiple-cell upset (MCU) and single word multiple-bit upset (SMU). 87
8.7.3 Single event functional interrupt (SEFI) . 89
8.7.4 Single event hard error (SEHE) . 90
8.7.5 Single event transient (SET) and single event disturb (SED) . 91
8.8 References . 92
9 Radiation-induced sensor backgrounds . 96
9.1 Introduction . 96
9.2 Background in ultraviolet, optical and infrared imaging sensors . 96
9.3 Background in charged particle detectors . 100
9.4 Background in X-ray CCDs . 100
9.5 Radiation background in gamma-ray instruments . 101
9.6 Photomultipliers tubes and microchannel plates . 104
9.7 Radiation-induced noise in gravity-wave detectors . 105
9.8 Other problems common to detectors . 105
9.9 References . 106
10 Effects in biological material . 108
10.1 Introduction . 108
10.2 Quantities used in radiation protection work. 108
10.2.1 Overview . 108
10.2.2 Protection quantities . 109
10.2.3 Operational quantities . 111
10.3 Radiation effects in biological systems . 113
10.3.1 Overview . 113
10.3.2 Source of data . 114
10.3.3 Early effects . 114
10.3.4 Late effects . 115
10.4 Radiation protection limits in space . 117
10.4.1 Overview . 117
10.4.2 International agreements. 117
10.4.3 Other considerations in calculating crew exposure . 118
10.4.4 Radiation limits used by the space agencies of the partners of the
International Space Station (ISS) . 118
10.5 Uncertainties . 122
10.5.1 Overview . 122
10.5.2 Spacecraft shielding interactions . 122
10.5.3 The unique effects of heavy ions . 122
10.5.4 Extrapolation from high-dose effects to low-dose effects . 123
10.5.5 Variability in composition, space and time . 123
10.5.6 Effects of depth-dose distribution . 123
10.5.7 Influence of spaceflight environment . 123
10.5.8 Uncertainties summary . 125
10.6 References . 125

Figures
Figure 1: CSDA range of electrons in example low- and high-Z materials as a function
of electron energy . 27
Figure 2: Total stopping powers for electrons in example low- and high-Z materials . 28
Figure 3: Intensity of mono-energetic protons in a beam as a function of integral
pathlength, . 29
Figure 4: Projected range of protons in example low- and high-Z materials as a function
of proton energy. . 30
Figure 5: Total stopping powers for protons in example low- and high-Z materials. . 30
Figure 6: Stopping power for electrons from collisions with atomic electrons and
bremsstrahlung production, and from bremsstrahlung production alone. . 32

Figure 12: Five electric effects due to defects in the semiconductor band gap [RDE.4] . 56
Figure 13: SEE initial mechanisms by direct ionisation (for heavy ions) and nuclear
interactions (for protons and neutrons). . 70
Figure 22: ISOCAM images for quiet conditions (top) and during solar flare event of
November 1997. . 98
Figure 23: Predicted and measured background spectra observed in OSSE instrument
on Compton Gamma-Ray Observatory 419 days after launch [RDG.10]. . 102
Figure 25: Relationship of quantities for radiological protection. . 113

Tables
Table 1: Summary of radiation effects parameters, units and examples. . 12
Table 2: Summary of radiation effects and cross-references to other chapters (part 1 of
2) . 13
Table 2: Summary of radiation effects and cross-references to other chapters (part 2 of
2) . 14
Table 3: Description of physics models (part 1 of 4) . 37
Table 3: Description of physics models (part 2 of 4) . 38
Table 3: Description of physics models (part 3 of 4) . 39
Table 3: Description of physics models (part 4 of 4) . 40
Table 4: Example radiation transport simulation programs which are applicable to
shielding and effects analysis. . 44
Table 5: NIEL rates for electrons incident on Si (from Summers et al based on Si
threshold of 21 eV [RDE.11]) . 61
Table 6: NIEL rates for protons incident on Si (part 1 of 2). This is a subset of NIEL
data from Huhtinen and Aarnio [RDE.12]. . 62
Table 6: NIEL rates for protons incident on Si (part 2 of 2). This is a subset of NIEL
data from Huhtinen and Aarnio [RDE.12]. . 63
Table 7: NIEL rates for neutrons incident on Si (part 1 of 2). This is a subset of NIEL
from Griffin et al [RDE.13]. . 64
Table 7: NIEL rates for neutrons incident on Si (part 2 of 3). These data are from
Konobeyev et al [RDE.14]. . 65
Table 7: NIEL rates for neutrons incident on Si (part 3 of 3). This is a subset of NIEL
from Huhtinen and Aarnio [RDE.12]. . 66
Table 8: NIEL rates for electrons in Si and GaAs (Akkerman et al [RDE.15]) . 67
Table 9: NIEL rates for protons in Si . 67
Table 10: NIEL rates for protons in GaAs. . 68
Table 11: Typical materials for UV, visible and IR sensors, with band-gap and electron-
hole production energies (e-h production energy for MCT is based on Klein
semi-empirical formula. . 97
Table 12: Lifetime mortality in a population of all ages from specific cancer after
exposure to low doses. . 116
Table 13: Estimates of the thresholds for deterministic effects in the adult human
testes, ovaries, lens and bone marrow. . 116
Table 14: CSA career ionising radiation exposure limits. . 119
Table 15: ESA ionising radiation exposure limits. . 119
Table 16: NCRP-132 recommended RBEs. . 119
Table 17: NCRP-132 Deterministic dose limits for all ages and genders (Gy-Eq.). . 120
Table 18: NCRP-132 career ionising radiation exposure limits. . 120
Table 19: NCRP-132 career effective dose limits for age and gender specific ionising
radiation exposure for 10-year careers. . 120
Table 20: JAXA short-term ionising exposure limits . 120
Table 21: JAXA career ionising radiation exposure limits (Sv). . 121
Table 22: JAXA current career exposure limits by age and gender . 121
Table 23: RSA short-term ionising exposure limits. . 121
Table 24: Russian career ionising radiation exposure limits . 122

European Foreword
This document (CEN/CLC/TR 17603-10-12:2021) has been prepared by Technical
Committee CEN/CLC/JTC 5 “Space”, the secretariat of which is held by DIN.
It is highlighted that this technical report does not contain any requirement but only
collection of data or descriptions and guidelines about how to organize and perform the
work in support of EN 16603-10-12.
This Technical report (CEN/CLC/TR 17603-10-12:2021) originates from ECSS-E-HB-
10-12A.
Attention is drawn to the possibility that some of the elements of this document may be
the subject of patent rights. CEN [and/or CENELEC] shall not be held responsible for
identifying any or all such patent rights.
This document has been prepared under a mandate given to CEN by the European
Commission and the European Free Trade Association.
This document has been developed to cover specifically space systems and has
therefore precedence over any TR covering the same scope but with a wider domain of
applicability (e.g.: aerospace).
Scope
This handbook is a part of the System Engineering branch and covers the methods for
the calculation of radiation received and its effects, and a policy for design margins.
Both natural and man-made sources of radiation (e.g. radioisotope thermoelectric
generators, or RTGs) are considered in the handbook.
This handbook can be applied to the evaluation of radiation effects on all space systems.
This handbook can be applied to all product types which exist or operate in space, as
well as to crews of on manned space missions.
This handbook complements to EN 16603-10-12 “Methods for the calculation of
radiation received and its effects and a policy for the design margin”.

Terms, definitions and abbreviated terms
2.1 Terms from other documents
For the purpose of this document, the terms and definitions from ECSS-S-ST-00-01 and
ECSS-E-ST-10-12C apply.
2.2 Terms specific to the present handbook
None.
2.3 Abbreviated terms
The abbreviated specified in ECSS-E-ST-10-12C apply to this handbook.
Compendium of radiation effects
3.1 Purpose
This clause provides a brief summary of the various mechanisms for radiation damage
and effects, and is summarised in the context in Table 1, which identifies important
parameters to quantify effects, and gives units and examples. Table 2 can be used by the
reader to cross-reference component/instrument technology to radiation effects
discussed in detail elsewhere in this document.
Table 1: Summary of radiation effects parameters, units and examples.
Effect Parameter Typical units Examples Particles
Total ionising dose Ionising dose in material grays (material) Threshold voltage shift and Electrons, protons,
(TID) (Gy(material)) or leakage currents in CMOS, bremsstrahlung
rad(material) linear bipolar (note dose-rate
sensitivity)
1 Gy = 100 rad
Displacement damage Displacement damage MeV/g All photonics, e.g. CCD Protons, electrons,
equivalent dose (total non- transfer efficiency, neutrons, ions

ionising dose) optocoupler transfer ratio

Equivalent fluence of 10 Reduction in solar cell
-2
cm
MeV protons or 1 MeV efficiency
electrons
2 2
Single event effects Events per unit fluence Memories, microprocessors. Ions Z>1
cm versus MeV⋅cm /mg
from linear energy transfer Soft errors, latch-up, burn-
from direct ionisation
(LET) spectra & cross- out, gate rupture, transients
section versus LET in op-amps, comparators.
Single event effects from Events per unit fluence cm versus MeV As above Protons, neutrons,
nuclear reactions from energy spectra &
ions
cross-section versus
particle energy
-1 -1
Payload-specific Energy-loss spectra, counts s MeV False count rates in detectors, Protons, electrons,
radiation effects charge-deposition spectra false images in CCDs neutrons, ions, induced
radioactivity (α, β±, γ)
charging Gravity proof-masses
Biological damage Dose equivalent = sieverts (Sv) or rems DNA rupture, mutation, cell Ions, neutrons,
Dose(tissue) x Quality death protons, electrons,
1 Sv = 100 rem
Factor;
γ-rays, X-rays
equivalent dose =
Dose(tissue) x radiation
weighting factor;
Effective dose
Charging Charge coulombs (C) Phantom commands from Electrons
ESD
Table 2: Summary of radiation effects and cross-references
to other chapters (part 1 of 2)
Sub-system or ECSS-E-ST-10-12C ECSS-E-HB-10-12A
Technology Effect
component Cross-reference Cross-reference
TID Clause 7 Clause 6
Power MOS SEGR Clause 9.4.1.6 Clause 8.6.2
SEB Clause 9.4.1.6 Clause 8.6.3
Clause 7
TID Clause 6
CMOS
Clause 9
SEE (generally) Clause 8
TNID Clause 8 Clause 7.4.2
SEU Clauses 9.4.1.2, 9.4.1.3 Clause 8.7.1
Integrated circuits Bipolar
SET Clause 9.4.1.7 Clause 8.7.5
TID Clause 7 Clause 6
TID Clause 7 Clause 6
BiCMOS TNID Clause 8 Clause 7.4.2
SEE (generally) Clause 9 Clause 8
TID Clause 7
Clause 6
SOI
SEE (generally exc. SEL) Clause 9 Clause 8
a
TID Clause 7 Clause 6
MEMS
TNID Clause 8 Clause 7.4.3
TID Clause 7 Clause 6
CCD
Enhanced background Clauses 10.4.2, 10.4.3, Clauses 9.2, 9.4
(SEE) 10.4.5
Clause 8 Clause 7.4.4
TNID
Clause 7 Clause 6
TID
CMOS APS Clause 9 Clause 8
SEE (generally)
Clauses 10.4.2, 10.4.3, Clauses 9.2, 9.4,
Enhanced background
10.4.5
TNID Clause 8 Clause 7.4.5
Photodiodes TID Clause 7 Clause 6
SET Clause 9.4.1.7 Clause 8.7.5
LEDs TNID Clause 8 Clause 7.4.7
laser LEDs TNID Clause 8 Clause 7.4.6
Optoelectronics and
sensors (1)
TNID Clause 8 Clause 7.4.8
Opto-couplers
SET Clause 9.4.1.7 Clause 8.7.5
TNID (alkali halides) Clause 8 Clause 7.4.11
γ-ray or X-ray
Enhanced background Clauses 10.4.2, 10.4.3, Clause 9.5
scintillator
10.4.4
TNID Clause 8 Clause 7.4.10
γ-ray semiconductor Enhanced background Clauses 10.4.2, 10.4.3, Clause 9.5
10.4.4
TNID (scintillator & Clause 8 Clause 9.5
semiconductor)
charge particle detectors Enhanced background Clause 10.4.2, 10.4.3 Clause 9.3
TID (scintillator & Clause 7 Clause 6
semiconductors)
microchannel plates Enhanced background Clause 10.4.6 Clause 9.6
photomultiplier tubes Enhanced background Clause 10.4.6 Clause 9.6
a
MEMS refers to the effects on the microelectromechanical structure only. Any surrounding microelectronics are also subject to other radiation
effects identified in “Integrated circuits” row

Table 2: Summary of radiation effects and cross-references
to other chapters (part 2 of 2)
Sub-system or Main Section Cross- ECSS-E-HB-10-12A
Technology Effect
component reference Cross-reference
Other imaging sensors
(e.g. InSb, InGaAs, TNID Clause 8 Clause 7
HgCdTe, GaAs and Enhanced background Clauses 10.4.2, 10.4.3 Clause 9.3
Optoelectronics and
GaAlAs)
sensors (2)
gravity wave sensors Enhanced background Clause 10.4.7 Clause 9.7
cover glass & bonding
TID Clause 7 Clause 6
materials
Solar cells
cell TNID Clause 8 Clause 7.4.9
crystal oscillators TID Clause 7 Clause 6
Non-Optical materials
polymers TID (radiolysis) Clause 7 Clause 6
silica glasses TID Clause 7 Clause 6
Optical materials
TID Clause 7 Clause 6
alkali halides
TNID Clause 8 Clause 7.4.11
Early effects Clause 11 Clauses 10.3.3, 10.4.4
Radiobiological effects Stochastic effects Clause 11 Clauses 10.3.4, 10.4.4
Deterministic late effects Clause 11 Clauses 10.3.4, 10.4.4

3.2 Effects on electronic and electrical systems
3.2.1 Total ionising dose
Total ionising dose (TID) effects in semiconductor devices depend on the creation of
electron-hole pairs within dielectric layers (oxides, nitrides, etc.) by the incident
radiation and subsequent generation of:
• traps at or near the interface with the semiconductor;
• trapped charge in the dielectric.
This can produce a variety of device effects such as flatband and threshold voltage
shifts, surface leakage currents, and noise [RDA.1].
TID effects in semiconductors are discussed further in Clause 7 of ECSS-E-ST-10-12C,
and Clause 6 of the present handbook.
3.2.2 Displacement damage
Energetic particles such as neutrons, protons, electrons, α-particles and heavy ions can
create damage in semiconductor materials by displacing atoms in the crystal lattice.
Secondary electrons produced by high-energy photons also produce displacement
effects. The result is that stable defect states are created within the bandgap that can

give rise to a variety of effects depending on the temperature, carrier concentration and
the location of the defect site [RDA.2]:
• Generation of electron-hole pairs (leading to thermal dark current in detectors).
• Recombination of electron-hole pairs (leading to reduction of minority carrier
lifetime and effects in LEDs and laser diodes).
• Trapping of carriers, leading to loss in charge transfer efficiency in CCDs
(minority carrier trapping) or carrier removal (majority carrier trapping).
• Compensation of donors or acceptors, also leading to carrier removal in some
devices (for example the resistance in a lightly doped collector in a bipolar
transistor can increase).
• Tunnelling of carriers (leading to increased current in reverse biased junctions –
particularly for small bandgap materials and high electric fields).
Displacement damage effects in semiconductors is discussed further in Clause 8 of
ECSS-E-ST-10-12C and Clause 7 of the present handbook.
3.2.3 Single event effects
Single event effects (SEEs) arise from the interaction of single particles (e.g. protons,
neutrons or heavy ions) with the semiconductor causing either destructive (or
potentially destructive) effects or transient effects.
• Destructive
• Single event latch-up (SEL) in CMOS circuits – a potentially destructive
triggering of a real or parasitic pnpn thyristor structure in the device;
• Single event snapback (SESB) in NMOS devices, particularly in SOI
devices – a destructive triggering of a lateral NPN transistor
accompanied by regenerative feedback [RDA.3];
• Single event gate rupture (SEGR) – Formation of a conducting path
triggered by a single ionising particle in a high-field region of a gate
oxide [RDA.4];
• Single event dielectric rupture (SEDR) – destructive rupture of dielectric
triggered by a single ionising particle in a high-field region of a dielectric
e.g. in linear devices, FPGAs;
• Single event burnout (SEB) in power transistors – a destructive
triggering of a vertical n-channel transistor accompanied by regenerative
feedback.
• Non-destructive
• Single event upset (SEU) in memories and registers – i.e. bit-flips
leading to change of stored information [RDA.5];
• Multiple-cell upsets (MCU) in memories and registers (including single-
word multiple-bit upsets (SMU)) – single particle impacts affecting
several adjacent bits due to large particle ranges
[RDA.6][RDA.7][RDA.8];
• Several logically adjacent bits corrupted in a digital element that have
been caused by direct ionisation from a single traversing particle or by
recoiling nuclei from a nuclear interaction, i.e. multiple bit upsets within
a single data word.
• Single event functional interrupt (SEFI) in control circuitry, e.g. in
processors, memories or ADCs – transient corruption of a control path
[RDA.9];
• Single event hard errors (SEHE) in SRAM and DRAM devices – where
semi-permanent damage is sustained by the memory cell due to micro-
dose effect from the ionising particle;
• Single event transients (SET) in linear circuits – i.e. a current transient
which can be interpreted as a false signal [RDA.10][RDA.11][RDA.12];
• Single event disturb (SED) in digital circuits – i.e. a signal transient that
is propagated to cause an output error in combinatorial logic.
Further information on single event effects is presented in Clause 9 of ECSS-E-ST-10-
12C and Clause 8 of the present handbook.
3.3 Effects on materials
Although TID effects are usually considered in the context of microelectronics or active
sensors, exposure to ionising radiation at high doses can also degrade polymers
(including those used in thermal blankets) and optical materials. In the case of the
former, radiolytic reactions occur in which the bonds in the polymer chains are broken
and formed with other reactive fragments. The result can be degradation of mechanical
and dielectric properties, coloration, and production of gases that can contaminate and
corrode nearby materials. Other optical materials such as silica glasses can also suffer
coloration and therefore degradation of their optical properties, depending upon the
purity of the material. These effects, together with TID effects in microelectronics, are
discussed further in Clause 7 of ECSS-E-ST-10-12C and Clause 6 of the present
handbook.
As with TID effects, displacement damage can also have deleterious effects on the
properties of passive materials. Atomic displacements in optical materials based on
alkali halides result in the production of colour centres (charge traps in the band-gap),
and therefore darkening of the crystal. This is discussed further in Clause 8 of ECSS-E-
ST-10-12C and Clause 7 of the present handbook.
3.4 Payload-specific radiation effects
Payloads can incorporate instruments which can suffer detrimental effects under
irradiation, in the main resulting in enhanced background levels, e.g.:
• Direct ionisation from primary or prompt secondary particles (e.g. in CCDs);
• Added background noise in sensors due to the various mechanisms, e.g. random
telegraph signals (RTS) discussed in Clause 8 of ECSS-E-ST-10-12C and Clause
7 of the present handbook;
• Gamma-ray detectors are sensitive to radioactive decays even outside regimes of
intense particle radiation [RDA.13][RDA.14];
• It is known that high temperature superconductors, proposed for gravity-wave
missions, can suffer a reduction in critical temperature under irradiation
[RDA.15]. Intense radiation regimes can lead to macroscopic temperature
changes in cryogenically cooled materials [RDA.16].
The use of high-mass spacecraft and detector systems necessitates the accurate
computation of secondary radiation and its spectrum to the point of energy/charge
deposition within the detector bandwidth.
Radiation background effects are discussed further in Clause 10 of ECSS-E-ST-10-12C
and Clause 9 of the present handbook.

3.5 Biological effects
Ionisation produces free hydroxyl radicals which compromise one or more of the
functions of the cell, this cellular damage becoming apparent after several cycles, or
even resulting in immediate cell death. The effects of this can be deterioration of tissue
or organ function, presenting within a matter of minutes to 30-60 days after exposure
(early radiobiological effects). Stochastic radiobiological effects can occur over the
duration of the life of the individual exposed and appears in the form of neoplastic
diseases (tumours). These are very probably the results of DNA damage to, and
subsequent mutation of, a single cell. In addition to long-term stochastic effects,
deterministic late effects are possible, such as the development of eye cataracts, which
definitely occur beyond a threshold dose. Individual relativistic high-Z particles can
also produce light flashes in the retina. These effects are discussed further in Clause 11
of ECSS-E-ST-10-12C and Clause 10 of the present handbook.
3.6 Spacecraft charging
Spacecraft charging can arise from energetic plasmas (10s of keV), leading to surface
c
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